1. Field of the Invention
The present invention relates to an ink-jet recording medium that can be suitably used in an ink-jet recording method. More particularly it relates to a recording medium having a superior absorption and color-forming performance for a water-based ink, and also capable of achieving a superior storage stability of recorded images obtained. It also relates to an ink-jet recording method making use of such a medium.
2. Related Background Art
Hitherto known recording mediums used for ink-jet recording include;
(1) those comprising an ordinary paper mainly composed of pulp, so made as to have a low degree of sizing as in filter paper or blotting paper; and PA1 (2) those comprising a substrate such as an ordinary wood free paper, having a low ink absorption, and an ink-absorbing layer provided thereon using a porous inorganic pigment, as disclosed in Japanese Patent Application Laid-open No. 56-148585.
In an ink-jet recording system that forms a color image with a high quality level and a high resolution, there is a demand for a particularly good image storage stability. Because of such a demand, methods of improving resistance to the fading of images due to sunlight, visible light, ultraviolet light, etc. are known in the art (see, for example, Japanese Patent Applications Laid-open No. 60-49990 and No. 61-57380).
Recently, however, the problem of indoor color changes of recorded images have been highlighted as a problem peculiar to coated papers.
The light-resistance having been hitherto questioned is a problem of the fading of images that is caused by irradiation with, e.g., ultraviolet light or visible light. This is a problem that may arise also in respect of images printed on any paper including all sorts of what is called PPC paper, commonly available, wood free paper, and coated paper for ink-jet recording. The problem of indoor color changes, referred to in the present invention, may also arise with respect to, for example, images formed on a coated paper stored at a place not directly exposed to sunlight, but on the other hand does not arise in respect of images printed on a non-coated paper such as PPC paper. This is a problem different from the above problem of light-resistance.
Since the problem of indoor color changes is a problem peculiar to coated papers as stated above, this problem is considered to arise from the pigment that constitutes a coat layer. The indoor color changes are known to be concerned with the specific surface area of the pigment used, and hence the indoor color changes can be suppressed if usual fillers for paper are used, as exemplified by calcium carbonate, kaolin and talc, having a small specific surface area. Since, however, image density and chrome are lowered when these fillers are used, there has been the problem that it becomes impossible to obtain images with a high quality level and a high resolution. Inversely, in the case of a coated paper making use of silica, having a large specific surface area and a strong activity, as disclosed, for example, in Japanese Patent Application Laid-open No. 56-185690, an image with a high optical density or chrome can be obtained but on the other hand there has been the disadvantage that the problem of indoor color changes becomes serious.
As stated above, the suppressing of indoor color changes and the problem of image density or chrome conflict with each other, and this problem has not been solved by any prior art.